Digit Ratio: A Pointer to Fertility, Behavior, and Health

Digit Ratio: A Pointer to Fertility, Behavior, and Health

by John Manning
     
 

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ISBN-10: 081353030X

ISBN-13: 9780813530307

Pub. Date: 01/28/2002

Publisher: Rutgers University Press

Could the length of your fingers indicate a predisposition to breast cancer? Or musical genius? Or homosexuality? In Digit Ratio, John T. Manning posits that relative lengths of the second and fourth digits in humans (2D:4D ratio) does provide such a window into hormone- and sex-related traits.

It has been known for more than a century that men and women tend

Overview

Could the length of your fingers indicate a predisposition to breast cancer? Or musical genius? Or homosexuality? In Digit Ratio, John T. Manning posits that relative lengths of the second and fourth digits in humans (2D:4D ratio) does provide such a window into hormone- and sex-related traits.

It has been known for more than a century that men and women tend to differ in the relative lengths of their index (2D) and ring (4D) fingers, which upon casual observation seem fairly symmetrical. Men on average have fourth digits longer than their second digits, while women typically have the opposite. Digit ratios are unique in that they are fixed before birth, while other sexually dimorphic variables are fixed after puberty, and the same genes that control for finger length also control the development of the sex organs. The 2D:4D ratio is the only prenatal sexually dimorphic trait that measurably explains conditions linking testosterone, estrogen, and human development; the study of the ratio broadens our view of human ability, talent, behavior, disposition, health, and fertility. In this book, Manning presents evidence for how 2D:4D correlates with traits ranging from sperm counts, family size, musical genius, and sporting prowess, to autism, depression, homosexuality, heart attacks, and breast cancer, traits that are all linked with early exposure to sex hormones.

Product Details

ISBN-13:
9780813530307
Publisher:
Rutgers University Press
Publication date:
01/28/2002
Series:
Series in Human Evolution
Edition description:
New Edition
Pages:
192
Product dimensions:
6.10(w) x 9.20(h) x 0.50(d)

Table of Contents

Table of contents for DIGIT RATIO: A Pointer to Fertility, Behavior, and Health by John T. Manning




List of Figures
List of Tables
Preface and Acknowledgments
Sex and Population Differences
Associations with Testosterone and Estrogen
Assertiveness, Status, Aggression, Attractiveness, and the Wearing of Rings
Reproductive Success and Sexually Antagonistic Genes
Hand Preference, Verbal Fluency, Autism, and Depression
Birth Weight, Heart Attack, Breast Cancer, and Sex-Dependent Diseases
Male and Female Homosexuality
Music, Musicians, and Mate Choice
Sporting Ability, Running Speed, Spatial Perception, Football Players, and Male Competition
2nd to 4th Digit Ratio and Future Research
Bibliography
Index

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